The Allied Riflemen are better with short range than the Axis Riflemen due to the semiautomatic rifle. It is usually best to pop off two quick shots to kill, but more may be necessary for close-quarters hip firing. The M1 Garand becomes much less effective at extremely long ranges.

Axis Riflemen are better with medium range fighting because the bolt-action rifle they carry is slightly underpowered, and a chest or headshot is required to kill. Long-range shots often require two shots to kill, which makes this class very tricky to master because the time to manually cycle the bolt action gives enemies some, but not always enough, time to seek cover. The Kar98k is largely useless in close quarters, so switching to the P38 is necessary in tight areas.

The Thompson inflicts approximately the same amount of damage per shot as a pistol, but its high rate of fire and better ironsights make it a lethal weapon. Recoil is controllable because the gun only moves up between shots. At medium ranges, three to four-shot bursts may be required to maintain accuracy.

The MP40 again inflicts similar damage to a pistol. It has extreme recoil, but the rate of fire is low enough that the weapon always returns to approximately the same direction between shots, so range is somewhat greater than the Thompson. The low rate of fire, when coupled with minimal damage per shot, make this weapon difficult to use; however, with experience, players can do quite well with the MP40. High mobility is also an advantage.

This class has the unique ability to revive fallen comrades. If the Medic approaches a fallen ally, the Medic can use the class ability to revive and ready them for battle. After the Medic has used the revive ability, the Medic must wait until the Special Ability meter on the right side of the screen fills before the Medic can use it again.

The trench gun used by Medics is extremely lethal at close range, but largely useless at any range other than close quarters. For more distant enemies, the player may need to switch to his sidearm or swap for a dropped weapon. The shotgun is pump-action, so the amount of time between shots may be an extreme disadvantage at times. Trench guns can be very useful in close quarters such as the bunkers of Verdun or the bridge and buildings in Eder Dam. Players can revive members of their own team who have been killed, which adds to their score, but does not increase the team's score in Team Deathmatch.

This class is useful for those who prefer long-range combat. It comes with a Sniper Rifle, and has the unique ability to use the Binoculars to call in Artillery Strikes on enemies. After the Scout has used the special ability, he must wait until the Special Ability meter on the right of the screen fills before being able to use the ability again. As the Scout ranks up, his artillery strike will come in faster and fire more shells thus making it more deadly and destructive.

Scouts are equipped with a scoped rifle that usually kills in one shot at any range. It is generally difficult to use at close range, particularly with the time necessary to cycle the bolt action. When standing, the scope will move around the screen to simulate the inaccuracy resulting from the soldier's breathing; this effect is reduced when crouching, and reduced further when prone. The player may hold L3 to simulate the soldier holding his breath, but must adjust to this quickly.

This class starts with a Machine Gun that can be set up on the ground or a ledge to rain fire on opponents from a stationary position. Support also has the ability to drop ammo packs to refill allies' weapons. After achieving higher ranks, the number of ammo packs the Support class can drop increases. There is a delay between dropping ammo packs.

Support is most effective against moving vehicles because their powerful machine gun allows them to destroy vehicles faster than other classes. However, it is not recommended to use a support class to attack a tank, due to their high health. The best place to setup would be a window in a house or behind a fence, as the cover can make it more difficult for opponents to kill the player.

The primary weapon of the Anti-Armor class is a rocket launcher, either a Bazooka or a Panzerschreck, depending on what faction the player is. The Anti-Armor's sidearm is a pistol, either a M1911 or a Walther P38. The player also has the special ability of dropping ammo packs to help teammates. The number of ammo packs that can be dropped is affected by the player's rank. The player must wait until the Special Ability meter fills before dropping another ammo pack.

There are five preset classes available when playing multiplayer mode in Call of Duty: Modern Warfare 2. These classes give players access to weapons and perks that they may not yet have unlocked. Until the weapon or perk is unlocked, play will not count towards any associated challenges. For instance, if a player is using the Grenadier class before they have unlocked the M203 grenade launcher, kills made with the grenade launcher will not count towards unlocking the masterkey shotgun attachment, though they will count as FAMAS kills towards unlocking the M203 attachment. Once the M203 attachment is unlocked, further kills with it would count towards unlocking the shotgun attachment. Similarly, a player will have use of the listed deathstreaks and perks, like Scavenger, but until the player reaches level 13 to unlock Scavenger, no progress will be made towards the Scavenger challenges. Furthermore, when a Pro version of a perk is unlocked, it is also applied to the preset classes.

There are 5 preset classes for online play in Call of Duty: Black Ops. These classes are soon replaced when the player unlocks Create-A-Class. For System Link and offline Split-Screen, the player is able to customize their own classes in the options menu, with all weapons, attachments, equipment, grenades, and perks unlocked. Unlike Call of Duty: Modern Warfare 2, Pro Perks obtained are not applied to the Preset Classes.

When the player purchases and unlocks a new soldier, they can select from one of five default loadouts to begin playing with their new soldier. All of that soldier's online Multiplayer loadouts start with that loadout's weapons, attachments, equipment, and perks unlocked first, and their Assault Strike Packages with SAT COM, Guard Dog, and Maniac, and their Support Strike Packages with SAT COM, Ammo Crate, and Oracle. Loadouts 2 and 3 start their primary weapons with the SC-2010 and the Bizon. (Loadouts 4, 5, and 6 are locked, requiring 20, 25, and 30 Squad Points respectively to purchase)

Advanced Warfare multiplayer marks the returns of several old mechanics, with one being the Black Ops II Pick-10 Create-A-Class system, however in Advanced Warfare it's a Pick-13 system due to the fact that Scorestreaks are a part of the Create-A-Class.